Co-infections are receiving increased attention as critically important factors in susceptibility, pathogenesis, and transmission of disease. Some of these highly significant interactions are broadly appreciated in the scientific community, e.g., the incidence of tuberculosis more than doubles during the first year after acquisition of HIV, and bacterial pneumonia was responsible for more than 95% of all deaths during the 1918 influenza pandemic. However, much of this broad field remains unrecognized despite its potentially huge public health impact. For example, co-infections of different species of malaria alter virulence through competition for resources within the host, and the Th2-bias induced by chronic nematode infections affects susceptibility, pathogenesis, and response to vaccines for a number of important infections including schistosomiasis, malaria, and HIV. In general, these interactions are poorly studied at any level, but particularly so at the molecular level where one might expect new insights to lead to strategies for intervention. There is clearly an unmet need to develop and train cross-disciplinary scientists who can study co-infections from a broad perspective. We are planning a conference to exchange ideas, foster collaboration, and provide different perspectives for scientists in the co-infections field and junior scientists in training. The Specific Aims of the meeting are to provide a forum for the communication of the most recent advances in the co-infection field and to attract and prepare junior investigators including students and postdoctoral fellows to the field of co-infections. Co-infections affect the health of billions of people worldwide. However, the scientific community has yet to develop, let alone apply, the methods necessary to improve the health of co-infected individuals. There is clearly an unmet need to develop and train cross-disciplinary scientists who can study co-infections from a broad perspective. The proposed conference has been designed to exchange ideas, foster collaboration, and provide different perspectives for scientists in the co-infections field and junior scientists in training.